Develop Reference

Sending to all clients in a multithreaded client-server

I',m currently having a problem with regards to my code. A client should be able to send a string "messge#somestring" and if the server notices that it contains the "message#" substring it should send it to all users. However, what is happening is that it gets sent to just one user that sent the "pseudo-request" that I'm trying to implement. Here are my codes for reference:
import java.io.*;
import java.net.*;
import java.util.Vector;
public class server {
static ServerSocket ss;
static Socket s;
static DataInputStream dis;
static DataOutputStream dos;
static Integer maxNumofUsers=4;
static Vector<UserHandler> users;
public static void main(String[] args) throws Exception {
// TODO Auto-generated method stub
Integer currNumofUsers=0;
ss=new ServerSocket(7777);
users=new Vector<UserHandler>();
while(currNumofUsers<maxNumofUsers) {
s=ss.accept();
UserHandler uh= new UserHandler(s, "Player "+Integer.toString(currNumofUsers+1));
users.add(uh);
users.get(users.size()-1).start();//start a thread
currNumofUsers++;
for(int i=0; i<users.size(); i++) {//updates number of users present pero userhandler
users.get(i).updateUserSet(users);
}
}
System.out.println("Maximum number of players reached.");
}
}
class UserHandler extends Thread{
Socket s;
DataInputStream dis;
DataOutputStream dos;
Vector<UserHandler> users=new Vector<UserHandler>();
String username;
public UserHandler(Socket s, String username) {
// TODO Auto-generated constructor stub
this.s=s;
this.username=username;
}
public void run(){
try {
dis=new DataInputStream(s.getInputStream());
dos=new DataOutputStream(s.getOutputStream());
while(true) {
String message=dis.readUTF();
if(message.contentEquals("exit")) {
dos.writeUTF("exit granted");
close();
break;
}else if(message.contains("message#")){//group sms
for(int i=0; i<users.size(); i++) {
users.get(i).dos.writeUTF("henlo");
System.out.println("Wrote to "+users.get(i).username);
}
}else {
dos.writeUTF("Some String");
}
}
} catch (IOException e) {
// TODO Auto-generated catch block
try {
s.close();
} catch (IOException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
e.printStackTrace();
}
}
public void close() {
try {
for(int i=0; i<users.size(); i++) {
if(users.get(i).username==this.username) {
users.remove(i);
System.out.println("out");
for(int j=0; j<users.size(); j++) {
users.get(j).updateUserSet(users);
}
break;
}
}
dis.close();
dos.close();
s.close();
}catch(IOException e) {
e.printStackTrace();
}
}
public void updateUserSet(Vector<UserHandler> users) {
// TODO Auto-generated method stub
this.users=users;
}
}
For the server. for the client,
import java.net.*;
import java.util.Scanner;
import java.io.*;
public class client {
static Socket s;
static DataInputStream dis;
static DataOutputStream dos;
static gameWindow GUI;
static String username;
public static void main(String[] args) throws Exception {
try {
s=new Socket();
s.connect(new InetSocketAddress("127.0.0.1",7777), 5000);
System.out.println("Socket "+s.getInetAddress()+" has connected.");
username= JOptionPane.showInputDialog("Please input username: ");
} catch (IOException e) {
// TODO Auto-generated catch block
System.out.println("Cannot connect to server. Either the Server was not established or maximum number of players was reached.");
}
if(s.isConnected()){
try {
dis=new DataInputStream(s.getInputStream());
dos=new DataOutputStream(s.getOutputStream());
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
Scanner sc=new Scanner(System.in);
String msg;
while(true) {
msg=sc.nextLine();
dos.writeUTF(msg);
String rcv=dis.readUTF();
if (rcv.contentEquals("exit granted")) {
System.out.println("Socket "+s.getInetAddress()+" is closed.");
close();
break;
}else if(rcv.contains("array#")) {
String tobearr=rcv;
String[] arred=tobearr.split("#");
for(int i=0; i<arred.length; i++) {
System.out.println(arred[i]);
}
tobearr="";
}else if(rcv.contains("message#")) {
String grpsms=rcv.substring(8, rcv.length());
System.out.println(grpsms);
}
System.out.println(rcv);
rcv="";
}
}
}
private static void close() {
// TODO Auto-generated method stub
try {
dis.close();
dos.close();
s.close();
}catch(IOException e) {
e.printStackTrace();
}
}
}

Server closes after one client disconnect (JAVA)

My server closes after one clients disconnects,and I can write only one more message then it crashes.I wonder why,since I only close the client socket when it types "EXIT SERVER" .This is the exception it throws:
java.io.EOFException
This is my code :
import java.net.*;
import java.io.*;
public class ServerPeer extends Thread {
Socket _socket;
String username;
public ServerPeer(Socket _socket) {
this._socket = _socket;
}
public void sendMessage(String _username, String _message) throws IOException {
ObjectOutputStream _obj = new ObjectOutputStream(
_socket.getOutputStream());
_obj.writeObject(new Message(_username, _message));
_obj.flush();
}
public synchronized void run() {
try {
ObjectInputStream _ois = new ObjectInputStream(_socket.getInputStream());
Message _message;
while (_socket.isConnected()) {
_message = (Message) _ois.readObject();
String divide = _message.getAll().substring(0, _message.getAll().indexOf(":"));
username = divide;
Server.listofusers.add(username);
for (ServerPeer sp : Server.listofpeers) {
if (_message.getAll().contains("EXIT SERVER")) {
Server.listofpeers.remove(sp);
_socket.close();
}
if (_message instanceof PrivateMessage) {
PrivateMessage privm = (PrivateMessage) _message;
for (ServerPeer sp2 : Server.listofpeers) {
if (sp2.username.equals(privm.getReceiver())) {
sp2.sendMessage(divide, privm.getAll());
String priv = privm.getAll().replaceAll("/w", "");
System.out.println(priv);
break;
}
}
} else {
sp.sendMessage(divide, _message.getAll());
System.out.println(_message.getAll());
}
}
_ois = new ObjectInputStream(_socket.getInputStream());
}
} catch (IOException e) {
e.printStackTrace();
} catch (ClassNotFoundException e) {
e.printStackTrace();
}
}
}
Server Class:
import java.io.*;
import java.net.*;
import java.util.*;
public class Server {
static ServerConfig _svconfig = new ServerConfig();
public static ArrayList<ServerPeer> listofpeers = new ArrayList<ServerPeer>();
public static ArrayList<String> listofusers = new ArrayList<String>();
public static int i = 0;
// final static int _mysocket;
public static void main(String[] args) {
try {
final int _mysocket = _svconfig.getPORTNumber();
System.out.println("Wainting for clients.....");
ServerSocket _serversocket = new ServerSocket(_mysocket, _svconfig.getCLIENTSNumber());
while (listofpeers.size() <= _svconfig.getCLIENTSNumber()) {
Socket _clientsocket = _serversocket.accept();
ServerPeer _serverpeer = new ServerPeer(_clientsocket);
_serverpeer.start();
listofpeers.add(_serverpeer);
}
_serversocket.close();
} catch (MissingKeyException e) {
e.printStackTrace();
} catch (UnknownKeyException e) {
e.printStackTrace();
} catch (InvalidFormatException e) {
e.printStackTrace();
} catch (ConnectException e) {
e.printStackTrace();
} catch (BindException e) {
e.printStackTrace();
} catch (UnknownHostException e) {
e.printStackTrace();
} catch (IllegalArgumentException e) {
e.printStackTrace();
} catch (SecurityException e) {
e.printStackTrace();
} catch (SocketException e) {
System.out.println("You have been disconnected");
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
}
EDIT:
Exception thrown in the console of the client who disconnects:
java.io.EOFException
at java.io.ObjectInputStream$PeekInputStream.readFully(ObjectInputStream.java:2328)
at java.io.ObjectInputStream$BlockDataInputStream.readShort(ObjectInputStream.java:2797)
at java.io.ObjectInputStream.readStreamHeader(ObjectInputStream.java:802)
at java.io.ObjectInputStream.<init>(ObjectInputStream.java:299)
at ClientPeer.serverEcho(ClientPeer.java:35)
at ClientPeer.run(ClientPeer.java:44)
BUILD STOPPED (total time: 1 minute 26 seconds)

From what I can tell i'd guess your code is incorrect, but it hard to tell without more code.
At first glance it seems that if too many people connect to your server you just shut down the entire server not just those connections.
while (listofpeers.size() <= _svconfig.getCLIENTSNumber()) {
Socket _clientsocket = _serversocket.accept();
ServerPeer _serverpeer = new ServerPeer(_clientsocket);
_serverpeer.start();
listofpeers.add(_serverpeer);
}
_serversocket.close();
A better approach would be something like the following. If too many users try to connect, just close the users connection.
ServerSocket _serversocket = new ServerSocket(_mysocket, _svconfig.getCLIENTSNumber());
boolean alive = true;
while (alive) {
try {
//Keep accepting connection request
Socket clientRequest = _serversocket.accept();
//Check if too many user are connected
if (listofpeers.size() <= _svconfig.getCLIENTSNumber()) {
ServerPeer _serverpeer = new ServerPeer(_clientsocket);
_serverpeer.start();
listofpeers.add(_serverpeer);
}else{
//Reject connection if too many connected
clientRequest.close();
}
} catch (Throwable t) {
t.printStackTrace();
}
}
//When server dead close it down
_serversocket.close();
Hope this helps.

Your code must be exiting after the client thread is terminated, create a thread that has the server accept method that starts the client thread, something like this,
/**
*/
private class ServerListener extends Thread
{
/**
*/
public void run()
{
try
{
Socket clientSocket = socket.accept();
System.out.println("client connected => "+clientSocket.getInetAddress().getHostAddress());
ServerListener th = new ServerListener();
th.start();
ClientThread cth = new ClientThread(clientSocket);
cth.start();
clients.add(cth);
return;
}
catch (Exception e)
{
e.printStackTrace();
//Main.getInsatance().println(e);
//Main.getInstance().println("socket disconnected => "+clientSocket.getInetAddress().getHostAddress());
}
}
}

How to create a Global Client Socket in my Android Application?

Hello dear programmers ,
I am trying to make a tic tac toe game using android, my android application contains several activities, one of these activities can the allows client to send a message to the server asking if X user wants to challenge, if the user accepts the challenge the server messages me and we both move forward to another activity.
My server is running as a regular java code on my PC, this is my server code :
public class Server {
ServerSocket serverSocket;
ArrayList<ServerThread> allClients = new ArrayList<ServerThread>();
public static void main(String[] args) {
new Server();
}
public Server() {
// ServerSocket is only opened once !!!
try {
serverSocket = new ServerSocket(6000);
System.out.println("Waiting on port 6000...");
boolean connected = true;
// this method will block until a client will call me
while (connected) {
Socket singleClient = serverSocket.accept();
// add to the list
ServerThread myThread = new ServerThread(singleClient);
allClients.add(myThread);
myThread.start();
}
// here we also close the main server socket
serverSocket.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
class ServerThread extends Thread {
Socket threadSocket;
String userName;
boolean isClientConnected;
InputStream input;
ObjectInputStream ois;
OutputStream output;
ObjectOutputStream oos; // ObjectOutputStream
public ServerThread(Socket s) {
threadSocket = s;
}
public void sendText(String text) {
try {
oos.writeObject(text);
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
public void run() {
try {
input = threadSocket.getInputStream();
ois = new ObjectInputStream(input);
output = threadSocket.getOutputStream();
oos = new ObjectOutputStream(output);
userName = (String) ois.readObject();
isClientConnected = true;
System.out.println("User " + userName + " has connected");
while (isClientConnected) {
String singleText = (String) ois.readObject();
System.out.println(singleText);
for (ServerThread t : allClients)
t.sendText(singleText);
// oos.writeObject(singleText);
}
// close all resources (streams and sockets)
ois.close();
oos.close();
threadSocket.close();
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}
I use the communication between clients in only two activies, both activites contain the same connectUser() code :
public class MenuActivity extends Activity {
public static final String HOST = "10.0.2.2";
public static final int PORT = 6000;
static ConnectThread clientThread;
boolean isConnected;
static boolean isOnline = false;
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_menu);
runOnUiThread(new Runnable() {
public void run() {
connectUser();
}
});
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
public void connectUser() {
clientThread = new ConnectThread();
clientThread.start();
}
class ConnectThread extends Thread {
InputStream input;
OutputStream output;
ObjectOutputStream oos;
Socket s;
public void sendText(String text) {
try {
oos.writeObject(text);
System.out.println(text);
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
public void run() {
try {
s = new Socket(HOST, PORT);
output = s.getOutputStream();
oos = new ObjectOutputStream(output);
oos.writeObject(un);
isOnline = true;
isConnected = true;
new ListenThread(s).start();
} catch (UnknownHostException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
class ListenThread extends Thread {
Socket s;
InputStream input;
ObjectInputStream ois;
public ListenThread(Socket s) {
this.s = s;
try {
input = s.getInputStream();
ois = new ObjectInputStream(input);
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
public void run() {
while (isConnected) {
try {
final String inputMessage = (String) ois.readObject();
//do something with the message }
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}
}
I use this code this code to send message to the server :
clientThread.sendText(user + " " + opponent + " play");
The problem is that when I create the connection at the first activity, then move to the second activity I create another connection , which means so far I am having two connections, same with other clients and then the server seems to return a timed out error.
My question is how to do a global client variable that is created once and can be used in each activity. I saw many suggestions like socket service or asyntask , but I need more direction and help
Thanks in advance.

Add a sub class of Application to your project and update application tag and add this class as android:name:
<application
android:name="com.your.app.MyApplication"
...
and then create a static reference to your Socket connection in MyApplication class:
private static Socket connection;
and then add a static method to access this object:
public static Socket getConnection() {
if( connection == null) {
// initialize connection object here
}
return connection;
}
Now you have a global object!

How restart bluetooth service in bluecove?

I have desktop and android applications, which connected by bluetooth(in desktop side I use Bluecove 2.1.1 library). Desktop application create bluetooth service then android application connects to it. I want to add logout functionality from both desktop and android sides. For example in desktop app user click disconnect, both desktop and android apps reset their connections and should be able to connect again. Here is bluetoothService code for desktop side:
public class BluetoothService
{
private static final String serviceName = "btspp://localhost:"
// + new UUID("0000110100001000800000805F9B34F7", false).toString()
// + new UUID("0000110100001000800000805F9B34F8", false).toString()
+ new UUID("0000110100001000800000805F9B34F9", false).toString()
+ ";name=serviceName";
private StreamConnectionNotifier m_service = null;
private ListenerThread m_listenerThread;
private DataOutputStream m_outStream;
public BluetoothService()
{
Open();
}
public void Open()
{
try
{
assert (m_service == null);
m_service = (StreamConnectionNotifier) Connector.open(serviceName);
}
catch (IOException e)
{
e.printStackTrace();
}
}
public void Start()
{
try
{
StreamConnection connection = (StreamConnection) m_service
.acceptAndOpen();
System.out.println("Connected");
m_listenerThread = new ListenerThread(connection);
Thread listener = new Thread(m_listenerThread);
listener.start();
m_outStream = new DataOutputStream(connection.openOutputStream());
}
catch (IOException e)
{
// TODO Auto-generated catch block
e.printStackTrace();
}
}
public void Send(String message)
{
assert (m_listenerThread != null);
try
{
m_outStream.writeUTF(message);
m_outStream.flush();
System.out.println("Sent: " + message);
}
catch (IOException e)
{
// TODO Auto-generated catch block
e.printStackTrace();
}
}
public void Close()
{
try
{
m_service.close();
m_listenerThread.Stop();
m_listenerThread = null;
m_outStream.close();
m_outStream = null;
m_service = null;
}
catch (IOException e)
{
e.printStackTrace();
}
}
}
class ListenerThread implements Runnable
{
private DataInputStream m_inStream;
private boolean m_isRunning;
public ListenerThread(StreamConnection connection)
{
try
{
this.m_inStream = new DataInputStream(connection.openInputStream());
m_isRunning = true;
}
catch (IOException e)
{
// TODO Auto-generated catch block
e.printStackTrace();
}
;
}
public void run()
{
while (m_isRunning)
{
try
{
assert (m_inStream != null);
if (m_inStream.available() > 0)
{
String message = m_inStream.readUTF();
System.out.println("Received command: " + message);
CommandManager.getInstance().Parse(message);
}
}
catch (IOException e)
{
System.err.println(e.toString());
}
}
}
public void Stop()
{
m_isRunning = false;
try
{
m_inStream.close();
}
catch (IOException e)
{
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
for restarting service I do:
BluetoothService::Close();
BluetoothService::Open();
BluetoothService::Start();
but seems I cannot reconnect. Maybe I should create service with different name?

passive ftp in java - why is the stream not ready

yet another java problem ...
got a client which should connect to a server via passive mode.
it seems to work fine, i get the ip adress and the port and the passivesocket says that it's ready.
but the passivesocket.getInputStream isn't ready at all - so i can't read from it and don't get the response to LIST.
can't figure out why, any suggestions?
public synchronized void getPasvCon() throws IOException, InterruptedException {
// Commands abholen
// IP Adresse holen
Thread.sleep(200);
String pasv = commands.lastElement();
String ipAndPort = pasv.substring(pasv.indexOf("(") + 1,
pasv.indexOf(")"));
StringTokenizer getIp = new StringTokenizer(ipAndPort);
// holt die IP
String ipNew = ""; // IP für den neuen Socket
for (int i = 0; i < 4; i++) {
if (i < 3) {
ipNew += (getIp.nextToken(",") + ".");
} else {
ipNew += (getIp.nextToken(","));
}
}
Integer portTemp1 = new Integer( getIp.nextToken(","));
Integer portTemp2 = new Integer (getIp.nextToken(","));
portNew = (portTemp1 << 8 )+ portTemp2;
System.out.println(">>>>> " + ipNew + ":" + portNew);
try {
pasvSocket = new Socket(ipNew, portNew);
System.out.println("Socket verbunden: "+ pasvSocket.isConnected());
} catch (UnknownHostException e) {
System.out.println("Host unbekannt");
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
try {
fromPasvServer = new BufferedReader(new InputStreamReader(
pasvSocket.getInputStream()));
Thread.sleep(2000);
System.out.println("Streams bereit: " + fromPasvServer.ready() + " | " );
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
try {
writePasvCommands = new PrintWriter(pasvSocket.getOutputStream(),
true);
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
Thread.sleep(3000);
Thread pasvKonsole = new Thread(new PasvKonsole(this));
pasvKonsole.start();
}
public void LIST() throws IOException {
writeCommands.print("LIST\n");
writeCommands.flush();
}
public void run() {
try {
connect();
// getStatus();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
try {
USER();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
PASS();
try {
Thread.sleep(2000);
PASV();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
import java.io.IOException;
public class PasvKonsole extends Thread {
Client client;
public PasvKonsole(Client client) {
this.client = client;
}
public void run() {
System.out.println("========= PasvKonsole started");
while(true) {
try {
String lineP = client.fromPasvServer.readLine();
System.out.println("***" + lineP);
System.out.println("Ich bin da und tue auch was");
} catch (IOException e) {}
}
}
}

Added a Thread.Sleep and it works.